US3311361A - Induction furnace - Google Patents

Description

March 28, 1967 H. ZEPERNICK INDUCTION FURNACE 2 Sheets-Sheet 1 Filed March ll, 1964 ina-A7555?! v of Y ZZ INVENTOR Hermann Zeperm-ck 10m W Y@ im@ ATTORNEYS March 28, 1967 H. ZEPERNICK INDUCTION FURNACE 2 Sheets-Sheet 2 Filed March ll, 1964 a L? w i f fi y vmJ INVENTOR Hermann Zepcemick SY/3m J 20 Pw@ W ATTORNEYS United States Patent O "P 3,311,361 INDUCHGN FURNACE Hermann Zepernick, Dortmund-Brechten, Germany, as-

signor to Aktiengesellschaft Brown, Boveri @z Cie., Baden, Switzerland, a `teint-stoel; company Filed Mar. 11, 1964, Ser. No. 351,063 2 Claims. (Cl. 2616-34) This invention relates to induction furnaces.

There are known processes and devices for treating and casting material, more particularly iron, originating from a shaft furnace, for example a cupola furnace, which serves to pre-melt the material, wherein the metal melted in the shaft furnace is further treated in a subsequent electric furnace, the required alloy additives being admixed only in the electric furnace, in which any desired increase in temperature is also eected in the liquid metal bath before final casting.

For example, it is known to produce steel by such a process from cast iron remelted in the cupola furnace. Ordinary cast iron may also be improved in quality in this way.

It is also `already known for the metal flowing out of a cupola furnace in a discharge channel to be passed into a drum-shaped channel-heated induction furnace, and to be conveyed therefrom by means `of casting ladles to those points at which final casting is to be carried out. Such a horizontally disposed drum furnace enables the molten material to be introduced at one end of the drum and withdrawn at the other-end, so that continuous working can be carried out. Alloy `additives may readily be additionally melted in in such a channel-induction furnace following a cupola furnace, and it is also possible for the metal flowing from the cupola furnace into this furnace to have its temperature increased and to be mixed. Such a combination of a cupola furnace and a drumshaped channel-heated induction furnace is especially suitable for producing high quality cast iron.

However, the channel-heated induction furnace, in whatever way it is constructed, has the disadvantage that it is difficult to prepare, considerably more diflicult than a crucible induction furnace. In addition, the complicated run of the melting channel results in the lining of the channel-heated induction furnace having a considerably shorter life than that of the crucible induction furnace. This means that the channel induction furnace is relatively expensive to maintain and is out of operation for a fairly long time when it fails, while a crucible induction furnace can be prepared in a very short time because of the simple and conveniently accessi-ble crucible shape, and any crucible surfaces which may be corroded are reltaively easy to check `and repair. This is also the reason why the low frequency crucible induction furnace is more and more replacing the channel induction furnace throughout all fields of the melting art.

However, should it be desired simply to replace the drum-shaped channel-heated induction furnace by .a crucible induction furnace designed in the form yof :an elongated drum furnace in the known combination of a cupola furnace with a subsequent electric furnace, wherein the molten metal is conveyed from the cupola furnace to the electric furnace by means of a pouring channel, the resultant constructional embodiment of such `a crucible furnace would be extremely difficult and expensive.

However, if it is desired to combine a single crucible induction furnace, instead of a drum-shaped one, with a cupola furnace to give continuous working, the said single crucible induction furnace having a vertical axis and being capable, in the customary manner, of being tilted only about a single axis disposed below the pouring spout, this attempt fails because alloy additives would have to be 3,311,361 Patented Mar. 2S, 1967 ICC admixed in the crucible, even while the latter was being tilted, with the metal flowing in via la pouring channel from the cupola furnace, and because an increase in temperature must be effected during this time. However, the normal crucible induction furnace cannot comply with these requirements.

In order to avoid the disadvantages attendant upon known devices, and the above-mentioned difficulties, an induction furnace for continuous further treatment and casting of material, more particularly cast iron, originating from a shaft furnace which serves for premelting purposes is designed `according to the invention in the form of a channel-free crucible induction furnace, and comprises, on the side opposite to its -pouring spout, an inward pouring aperture associated with the discharge channel of the shaft furnace. This crucible induction furnace is furthermore capable of being tilted at will about at least two different tilting axes, first of all about an axis which is disposed below the inward pouring aperture when the crucible furnace is in its basic position, and about which the crucible can be tilted downwards for pouring purposes, and secondly about an axis which is disposed slightly below the pouring spout of the furnace when the latter is tilted downwards .about the first-named axis into its end position, and about which second axis the crucible furnace can be tilted upwards for the purpose of being completely emptied. In this connection, the body of the furnace including its inward pouring aperture is so arranged in relation to the discharge aperture of the shaft furnace as to be able to move freely past the discharge channel of the shaft furnace when :carrying out tilting movements about the above-named axes.

in a further development of the invention, the crucible furnace may also lbe capable of being tilted downwards about an Vaxis which is disposed slightly below the pouring spout when the furnace is in its basic position.

The fact that the crucible induction furnace according to the invention can carry out at will the tilting movements stated above enables, as Will be more precisely explained hereinafter, all the operations required when such a furnace is cooperating with a shaft furnace to be carried out in -continuous working in a single crucible induction furnace, which may otherwise be embodied as a crucible furnace of normal construction, that is to say having its crucible axis vertical when the said furnace is in its basic position, and thus having all the advantages of the normal crucible induction furnace. Only a few bearings are added for the purpose of carrying out the tilting movements described, with the result that the way in which the furnace itself is constructed-apart from an inward pouring aperture-is not affected.

The crucible furnace according to the invention may above all be a crucible induction furnace fed at low frequency, more particularly mains frequency, but the possibility of usingv the invention is not limited to the frequency range specified.

In order that the present invention may be well understood there will now be described one embodiment thereof, given by way of example only, reference being had to the accompanying drawings in which FIGURES l to 4 shown in longitudinal section a furnace embodying the invention and in different operating attitudes.

The furnace is shown in FIGURE 1 in its basic position. In this figure, 1 signifies the jacket of the body of the furnace, and 2 the ceramic heat insulation. 3 designates the crucible space, 4 the crucible, which is made of a stamped i.e. a compressed composition, 7 the cover of the furnace, and 5 the induction coil surrounding the crucible.

On the side opposite to the pouring spout 6, the furnace comprises an inward pouring aperture 8 associated with the discharge channel 16 of a shaft furnace, for example a cupola furnace, not illustrated.

The new type of furnace is so devised as to be capable of being tilted at will about the axes designated in FIG- URES 1-4 by A, B and C. For this purpose, the body of the furnace is provided below the inward pouring aperture S with bearings 10, which may for example each consist f bored anges fastened to the body of the furnace. The pedestal 14 of the furnace likewise comprises bearings corresponding to the tilting axis A. Pins 18, capable of lbeing introduced into the bores in these bearings and into the bores in the bearings 18 on the body of the furnace, enable the furnace to be rotatably supported at A (the pins 18 are shown separately lbeside FIGURES 1-4).

In order to pour ofIr the molten material, the furnace is tilted in the downward direction about the tilting axis A out of the basic position illustrated in FIGURE l into the position corresponding to FIGURE 2. In this connection, the pouring spout describes a shallow arc of a circle from a to b, and moves lower by the distance c.

Hydraulic tilting cylinders 11 may be provided on either side of the furnace in order to tilt it and return it to the basic position, acting on the `body of the furnace by way of their pressure pistons 12 and via spindles 13.

As may be seen in FIGURE 2, the molten metal may be continuously poured off during the tilting movement (from the position shown in FIGURE 1 to the position shown in FIGURE 2) into a ladle 1S placed in front of the furnace. This ladle may be suspended from the grab of a normal crane installation, and need only be varied in height according to how much the furnace is to be tilted. This advantage is attained as a result of the relatively long distance from the pouring spout 6 to the tilting axis A.

If FIGURES 1 and 2 are compared as regards the change in the position of the inward pouring aperture 8 when the furnace is tilted, it will be seen that molten metal may readily be conveyed by means of the metal-discharge channel 16 leading from the cupola furnace to the crucible furnace even while the latter is being tilted, the discharge channel 16 of the cupola furnace not having to change its position. The inward pouring aperture is so designed that the discharge channel 16 of the cupola furnace is not touched by the lower edge 17 of the inward pouring aperture 8 during downward tilting from the basic position into the position shown in FIGURE 2. The path d described by this edge in the course of the tilting movement and the associated radius e are shown in FIG- URE 1.

It may also be seen from FIGURE 2 that even after about 173 of the contents of the furnace have already been tipped out when the furnace is tilted into the position shown therein, the molten metal entering the furnace is still suiciently far from the pouring aperture of the shaft furnace to prevent it from pouring straight out of the furnace. Thus, if a crucible furnace according to the invention follows or is combined with a cupola furnace, it is possible both to admix alloy additives in the crucible furnace and attain thorough mixing of the molten metal with the alloy additives even while tilting is in progress.

In order to attain such mixing with an even greater degree of reliability, a transverse partition may be additionally provided in the crucible, reaching not quite as far as the base thereof, as indicated in dashed line at 21 in FIGURE 2. This forces the incoming metal to take a path low down in the crucible space before reaching the pouring spout 6. Moreover, if the crucible is well filled, the turbulence inductively imparted to the bath, shown by arrowed lines in FIGURE l, causes the molten material to become thoroughly mixed.

In this connection, the use of a low frequency crucible induction furnace according to the invention in conjunction with a cupola furnace gives better mixing and uniformity of temperature in the molten material, and thus an improvement in `alloy quality, as compared to the known combination of a cupola furnace with a drumshaped channel-heated induction furnace, because the electro-dynamically generated bath movement in la low Vfrequency crucible furnace is far stronger than in a channel-heated induction furnace. In this connection, mixing may even be continued while pouring is in progress.

Furthermore, there are further bearings 9 slightly below the pouring spout 6 of the furnace on both sides of the body thereof, which bearings may be of similar design to the aforementioned bearings 10. In this connection, the bearings 9 are so arranged as to be capable of being brought into alignment, as a result of the furnace being tilted about the tilting axis A, with bearings in the pedestal 19 corresponding to the tilting axes B -or C so that pins 1S capable of being introduced into the bores in the bearings 9 on the body of the furnace, and into the bores in those bearings in the pedestal of the furnace which are in alignment in each case with the bearings 9, can support the furnace so that it is rotatable in those bearings in its pedestal corresponding either to the tilting axis B or the tilting axis C.

The crucible furnace is illustrated in FIGURE 4 tilted into its highest position, which it can be caused to assume by pivoting about the tilting axis B, and in which the crucible can be completely emptied. For this purpose, pins 18 are inserted into the bores in the bearings 9 on the body of the furnace and into the bores in the bearings corresponding to the tilting axis B in the pedestal 19 of the furnace when the furnace is in a position corresponding to FIGURE 2, i.e. when the said bearings are in alignment. The furnace is then first of all lifted somewhat by means of the hydraulic driving device 11, 12, so that the pins 18 can be withdrawn from their bearings at A. In order to facilitate this, it is advisable to provide plenty of play for the pins in the corresponding bearings. The furnace may then be pivoted about the tilting axis B in the direction of the arrowed line shown in FIGURE 4 by means of the hydraulic drive, the crucible then being completely emptied, which may be required, for example, if the crucible must be prepared again. As may be seen 1n FIGURE 4, the body of the furnace then moves freely past the discharge channel 16 of the shaft furnace.

FIGURE 3 shows the crucible furnace according to the 1nvention in a position in which the furnace is tilted downwards about the -tilting axis C out of its basic position corresponding to FIGURE 1 (after the pin 18 has first of all been removed from the bearings at A).

Before this tilting .movement can be carried out, the pins 18 must be transposed, and this is done so that the furnace, which is in the basic position and is supported at IA, can first of all be lifted by means of the hydraulic drive 11, 12 far enough to enable pins 18 to be introduced at C. After the furnace has been further lifted to a slight extent, the pins may be easily removed at A, especially if plenty of play has been left in the bearings, as already mentioned. The furnace may then be tilted downwards about the tilting axis C far enough to enable a scraper tool 20 to be introduced through the inward pouring aperture 8 for de-slagging purposes. Any partitiondZl which gray be provided can readily be so designe as not to inder de-slagging, as ma be seen o FIGURE 3. The inward pouring apert/ure 8 of tlIiI; furnace can readily be so designed, as shown in the arrangement in FIGURE 3, so that its upper edge describes an arc of a circle from f to g, as shown by the dashed lines 1n FIGURE 3, when the furnace is tilted from the basic position into the position corresponding to FIGURE 3, so that the said edge moves freely past the forward end of the discharge channel 16 of the shaft furnace.

After de-slagging is finished, the furnace is lifted again and moved into the basic position in which the pin 18 is inserted into the corresponding bearings at A. If pouring is then to take place again, the pin is removed at C after the furnace has been slightly lifted, whereupon the tilting operation already described about the tilting axis A can be carried out.

The invention is not limited to the example of embodiment illustrated. Various modifications thereof, more particularly of a Constructional nature, are conceivable. Thus, the Crucible induction furnace according to the invention may be provided in intrinsically known manner with stacks of iron laminations surrounding the Crucible. However, an induction Crucible furnace without any such stacks of iron laminations may also be used.

The furnace according7 to the invention is suitable above all for producing refined cast iron, but the inven tion is in no way limited thereto. It may also be used with advantage in appropriate Cases for producing other sorts of iron, and also for steel production.

I Claim:

1. An induction furnace for the Continuous further treatment and casting of metal such as iron which originates from a shaft furnace and which serves for premelting the metal, said induction furnace being channelfree and of the Crucible type and which includes at opposite sides of said Crucible respectively at the upper part thereof a pouring-off spout and `a pouring-in aperture adapted to register with a discharge channel of said shaft furnace, first and second bearing pedestals located respectively at said opposite sides of said Crucible, said first bearing pedestal located at the side of said Crucible provided with said pouring-in aperture including a rst bearing means alignable with a cooperating first bearing means located on said Crucible below said pouringin aperture and Connectable therewith by a removable pin so as to establish a first pivot axis for said Crucible by means of which said Crucible may be tilted from a basic essentially horizontal position to a downwardly inclined position providing a partial pour-olf of the cru- Cible contents, and said second bearing pedestal located at the side of said pouring-off spout including a lower t5 second and an upper third bearing means alignable alternatively with a cooperating second bearing means located on said Crucible below said pouring-off spout, said second bearing means on said Crucible being connectable alternatively with said second or third bearing means on said second pedestal by `a removable pin so as to establish a lower and second pivot axis for said Crucible by means of which said Crucible may be tilted upwardly from said downwardly inclined partial pour-off position when released from said first pivot axis so as to effect a complete emptying of the Crucible, and so as to establish an upper and third pivot axis for said Crucible by means of which said Crucible may be tilted downwardly in the opposite direction when released from said first pivot yaxis from said basic position to a point where said pouring-in aperture is removed from registration with said discharge channel of said shaft furnace and exposed to enable insertion of a scraper tool for de-slagging of the metal within the Crucible.

2. A Crucible type induction furnace as defined in Claim 1 wherein said Crucible is provided with an interior partition located parallel with said first, second and third pivot axes, the lower edge of said partition being spaced from the bottom of said Crucible and the upper edge thereof terminating below the surface level of the molten metal when said Crucible Contains its normal charge.

References Cited by the Examiner UNITED STATES PATENTS 863,469 8/1907 Thill et al 22-82 1,246,783 1l/1917 Reilly 22-82 2,385,206 9/1945 Hopkins 22-79 2,674,640 4/1954 Tama 266-38 3,201,224 8/1965 Grim 266-34 X FOREIGN PATENTS 145,737 3/ 1931 Switzerland.

JOHN F. CAMPBELL, Primary Examiner.

I. M. ROMANCHIK, Assistant Examiner.

Claims (1)

1. AN INDUCTION FURNACE FOR THE CONTINUOUS FURTHER TREATMENT AND CASTING OF METAL SUCH AS IRON WHICH ORIGINATES FROM A SHAFT FURNACE AND WHICH SERVES FOR PREMELTING THE METAL, SAID INDUCTION FURNACE BEING CHANNELFREE AND OF THE CRUCIBLE TYPE AND WHICH INCLUDES AT OPPOSITE SIDES OF SAID CRUCIBLE RESPECTIVELY AT THE UPPER PART THEREOF A POURING-OFF SPOUT AND A POURING-IN APERTURE ADAPTED TO REGISTER WITH A DISCHARGE CHANNEL OF SAID SHAFT FURNACE, FIRST AND SECOND BEARING PEDESTALS LOCATED RESPECTIVELY AT SAID OPPOSITE SIDES OF SAID CRUCIBLE, SAID FIRST BEARING PEDESTAL LOCATED AT THE SIDE OF SAID CRUCIBLE PROVIDED WITH SAID POURING-IN APERTURE INCLUDING A FIRST BEARING MEANS ALIGNABLE WITH A COOPERATING FIRST BEARING MEANS LOCATED ON SAID CRUCIBLE BELOW SAID POURINGIN APERTURE AND CONNECTABLE THEREWITH BY A REMOVABLE PIN SO AS TO ESTABLISH A FIRST PIVOT AXIS FOR SAID CRUCIBLE BY MEANS OF WHICH SAID CRUCIBLE MAY BE TILTED FROM A BASIC ESSENTIALLY HORIZONTAL POSITION TO A DOWNWARDLY INCLINED POSITION PROVIDING A PARTIAL POUR-OFF OF THE CRUCIBLE CONTENTS, AND SAID SECOND BEARING PEDESTAL LOCATED AT THE SIDE OF SAID POURING-OFF SPOUT INCLUDING A LOWER SECOND AND AN UPPER THIRD BEARING MEANS ALIGNABLE ALTERNATIVELY WITH A COOPERATING SECOND BEARING MEANS LOCATED ON SAID CRUCIBLE BELOW SAID POURING-OFF SPOUT, SAID SECOND BEARING MEANS ON SAID CRUCIBLE BEING CONNECTABLE ALTERNATIVELY WITH SAID SECOND OR THIRD BEARING MEANS ON SAID SECOND PEDESTAL BY A REMOVABLE PIN SO AS TO ESTABLISH A LOWER AND SECOND PIVOT AXIS FOR SAID CRUCIBLE BY MEANS OF WHICH SAID CRUCIBLE MAY BE TILTED UPWARDLY FROM SAID DOWNWARDLY INCLINED PARTIAL POUR-OFF POSITION WHEN RELEASED FROM SAID FIRST PIVOT AXIS SO AS TO EFFECT A COMPLETE EMPTYING OF THE CRUCIBLE, AND SO AS TO ESTABLISH AN UPPER AND THIRD PIVOT AXIS FOR SAID CRUCIBLE BY MEANS OF WHICH SAID CRUCIBLE MAY BE TILTED DOWNWARDLY IN THE OPPOSITE DIRECTION WHEN RELEASED FROM SAID FIRST PIVOT AXIS FROM SAID BASIC POSITION TO A POINT WHERE SAID POURING-IN APERTURE IS REMOVED FROM REGISTRATION WITH SAID DISCHARGE CHANNEL OF SAID SHAFT FURNACE AND EXPOSED TO ENABLE INSERTION OF A SCRAPER TOOL FOR DE-SLAGGING OF THE METAL WITHIN THE CRUCIBLE.

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